A New Fault-tolerant Control of Battery Energy Storage Grid-connected System Based on Cascaded H-Bridge

Cascaded H-Bridge (CHB) converter has high output power quality, which can be used in energy storage grid connected systems to control charging and discharging of batteries. But this system contains a large number of switching devices and energy storage batteries, increasing the probability of failure. The traditional fault-tolerant control is not suitable when the state-of-charge (SOC) initial values of the battery modules are not the same. Therefore, a new control strategy is proposed in this paper, which only needs to inject zero-sequence voltage once and makes system control simpler and more efficient. Through MATLAB/Simulink and experiments, it has been proven that the proposed fault-tolerant control can not only maintain normal operation in the event of system failure, but also greatly improve the SOC balance speed.